Spool gripper, spool handling unit with spool gripper, and method of handling spool using same

ABSTRACT

A spool gripper is coupled to any one of the flanges provided at both sides of a spool wound with a semiconductor device bonding wire thereon. The spool gripper has an inner diameter portion for receiving a spool holder when the spool is fitted to the spool holder, a coupling portion coupled to the circumference of the flange while bearing a diameter larger than the inner diameter portion, and an outer diameter portion with a diameter larger than the coupling portion. The worker grips the outer diameter portion to handle the spool. The handling of the spool can be made without directly touching the spool. The wire bonding operation is made while the gripper is coupled to the flange. Therefore, it is not necessary to decouple the gripper from the flange to make the wire bonding operation. Accordingly, the durability of the gripper and the reliability in the spool holding can be maintained without deterioration while preventing separation of the spool from the gripper. Irrespective of the length of the spool holder or the presence of the spool fixation member, the spool handling unit can be used with any type spool holder.

BACKGROUND OF THE INVENTION

[0001] (a) Field of the Invention

[0002] The present invention relates to a wire bonding assembly forprocessing a semiconductor chip package and, more particularly, to aspool gripper detachably fitted to a spool flange. The invention furtherrelates to a method of handling a spool with the spool gripper whicheffectively prevents a bonding wire from being contaminated and damageddue to the carelessness of a worker.

[0003] (b) Description of the Related Art

[0004] Generally, a wire bonding assembly is a device for electricallyconnecting a lead of a lead frame to a bonding pad of a semiconductorchip bearing an electrical characteristic by way of a conductive wiresuch as a high purity platinum Pt wire or an aluminum wire.

[0005] The wire bonding assembly is usually provided with a spool, aspool holder, a wire feed guider, a wire clamp, and a capillary. Aconductive wire is wound on the spool, and the spool is fitted to thespool holder. The conductive wire is fused by way of the capillary andthe torch bar, and welded to the bonding pad of the semiconductor chipand the lead.

[0006] In order to prevent the conductive wire from being separated fromthe spool while making the worker hold the spool and fit it to the spoolholder, a flange is formed at both sides of the spool such that itprotrudes from the spool by 4-5 mm in a radial manner. Various kinds ofspool cases may be used to handle the spool. The handling of the spoolmay be storage and carriage thereof.

[0007] For instance, Japanese Utility Model Publication Number Sho54-103747 discloses a spool case having a base with a protrusion ontowhich a cylindrical spool is inserted, and a cover coupled to the baseto prevent a foreign material such as dust from being introducedtherein. The cover is provided with a depressed portion for receivingthe spool in correspondence with the protrusion of the base.

[0008] With the above-structured spool case, the worker grips the flangeof the spool by hand to remove the spool from the spool case, and atthat state, fits it to the spool holder.

[0009] However, as the spool flange is radially protruded from the spoolat most by 4-5 mm, the wire wound on the spool becomes placed over theoutermost circumference of the flange. Accordingly, with the handling ofthe spool, the fingers of the worker contact the surface of theconductive wire. In this case, the wire is contaminated or damaged, andthis induces serious device failures during the wire bonding process.

[0010] Korean Utility Model Publication No. 97-52837 discloses a spoolhaving a one-sided flange with a first diameter, and an opposite-sidedflange with a second diameter. The second diameter is established to besignificantly larger than the first diameter. The worker grips the largediameter flange to fit the spool to the spool holder.

[0011] Japanese Patent Publication Laid-open No. 2000-012599 discloses abonding wire spool case with a base. The base has an interfacialcoupling member externally fitted around the spool flange to hold thespool, and a knob externally protruded to receive a spool holder. Thebase is established to be capable of being elastically transformed. Inorder to decouple the spool from the base, the worker grips the knob,and elastically transforms the base.

[0012] However, such a spool with a large diameter flange involvesseveral problems.

[0013] The spool used in the wire bonding assembly may be differentiatedin structure per the respective semiconduct^(o)or chip packagemanufacturing companies. For instance, it is possible that the A companyuses a spool where only the one-sided flange is formed with a largediameter, whereas the B company uses a spool where all of the both-sidedflanges are formed with a small diameter (4-5 mm). With this situation,in order to supply the correct spools to both of the A company and the Bcompany, the spool manufacturing company should make a facility forproducing the former-type flange and a facility for producing thelatter-type flange in a separate manner. This inevitably causesincreased production cost.

[0014] Meanwhile, with the spool case disclosed in Japanese PatentPublication Laid-open No. 2000-012599, the base with the interfacialcoupling member is formed with a material capable of being elasticallytransformed such that the spool can be decoupled from the base by way ofthe interfacial coupling member.

[0015] In case the base repeatedly suffers the elastic transformation incoupling or decoupling the spool, stress is made at a predeterminedregion of the base due to the elastic transformation. Consequently, thebase is stress-damaged while being deteriorated in its durability.

[0016] The interfacial coupling member, which is connected to the basein a body to substantially hold the spool, is formed with an elasticplastic material. With the repeated uses, the interfacial couplingmember becomes worn out or blunt, and this deteriorates reliability inthe spool holding operation.

[0017] Furthermore, with the handling of the spool, the worker picks outthe cover from the base, and grips the base to fit the spool to thespool holder of the bonding assembly. At this time, the worker mayinattentively grip both sides of the base. In this case, the spoolholding operation by way of the interfacial coupling member is released,and as a result, the spool is decoupled from the base. Consequently, thebonding wire is contaminated, and damaged.

[0018] Furthermore, in case the spool holder is longer than the sum inlength of the spool and the knob, the spool is incompletely fitted tothe spool holder so that the spool coupling and decoupling operation byway of the base cannot be easily made. In case the spool holder has aholder knob at its end portion, the holder knob is internally caught bythe knob of the base so that the spool coupling and decoupling operationusing the base becomes impossible while delimiting the usable range ofthe spool case.

SUMMARY OF THE INVENTION

[0019] It is an object of the present invention to provide a grippercapable of being coupled to or decoupled from a spool flange, and a unitand a method of handling a spool with the gripper.

[0020] This and other objects may be achieved by a spool gripper and aspool handling unit with the following features.

[0021] A spool gripper is coupled to any one of flanges provided at bothsides of a spool wound with a semiconductor device bonding wire thereon.The spool gripper has an inner diameter portion for receiving a spoolholder when the spool is fitted to the spool holder, a coupling portioncoupled to the circumference of the flange while bearing a diameterlarger than the inner diameter portion, and an outer diameter portionwith a diameter larger than the coupling portion.

[0022] With the spool gripper, the facility cost is not increased whilesatisfying the requirements of the package manufacturing company. Incase spools are delivered to the package manufacturing company where thedesired spool has a large diameter flange, the delivery is made with thegripper being coupled to the flange of the spool. Therefore, anadditional facility for making a large diameter flange is not needed.

[0023] Furthermore, the distance between the bonding wire wound on thespool and the outer diameter portion of the gripper becomes enlarged tobe greater than that related to the conventional small diameter flange.Therefore, the handling of the spool can be made without directlytouching the spool. The coupling state of the gripper to the spool isnot released unless the gripper is intentionally separated from theflange. As the wire bonding operation is made while the gripper iscoupled to the flange, it is not needed that the gripper should bedecoupled from the flange to make the wire bonding operation.Accordingly, the durability of the gripper and the reliability in thespool holding can be maintained without deterioration while preventingseparation of the spool from the gripper.

[0024] At least two coupling protrusions are formed at the couplingportion while protruding inwardly in a radial manner. The couplingprotrusion may be positioned at the periphery of the coupling portion,or at the center thereof.

[0025] The coupling protrusion should be formed at the same height asthe thickness of the flange to fit the gripper to the flange. With theplacing of the coupling protrusion at the middle of the couplingportion, the thickness of the outer diameter portion is enlarged by apredetermined degree. Accordingly, when the worker grips the gripper,the fingers of the worker do not touch the conductive wire W.

[0026] A plurality of prominent portions are formed at the gripper tomake a space for receiving the end of the conductive wire W fastened tothe outer surface of the spool flange by way of a tape. When the gripperis coupled to the spool flange, the end of the conductive wire W isplaced within the space, and hence, possible damage thereof can beprevented.

[0027] The gripper may be formed with a metallic plate ring, or aplastic plate ring. In the latter case, it is preferable that cuttingplanes are formed at the gripper. When the worker grips the gripper, thegripper can be transformed while compressing the inner diameter portion,due to the presence of the cutting planes. Accordingly, with thegripping of the gripper, the spool can be securely coupled to thegripper without separation.

[0028] A spool handling unit with the gripper includes a spool case forstoring the spool. The spool case has a base for mounting the spool, anda cover coupled to the base to prevent foreign materials such as dustfrom being introduced. The base has a bottom portion, a sidewallprotruded from the bottom portion, and a protrusion formed at the bottomportion internal to the sidewall while being inserted into the innerdiameter portion of the spool. The cover has a protrusion inserted intothe inner diameter portion of the spool fitted to the base to hold thecentral axis of the spool in the horizontal direction.

[0029] The central axis of the spool is placed at a horizontal plane ina stable manner. Accordingly, the bonding wire W wound on the spooldeals well with its own load, vibration in its movement and otherimpacts over its entire length while effectively preventing theunintended winding or releasing thereof.

[0030] A stopper may be formed at the cover to make the central axis ofthe spool be kept to be in the horizontal direction.

BRIEF DESCRIPTION OF THE DRAWINGS

[0031] A more complete appreciation of the invention, and many of theattendant advantages thereof, will be readily apparent as the samebecomes better understood by reference to the following detaileddescription when considered in conjunction with the accompanyingdrawings in which like reference symbols indicate the same or thesimilar components, wherein:

[0032]FIG. 1 is a perspective view of a spool gripper according to apreferred embodiment of the present invention;

[0033]FIG. 2 is a cross sectional view of the spool gripper taken alongthe A-A line of FIG. 1;

[0034]FIG. 3 is a cross sectional view of the spool gripper taken alongthe A-A line of FIG. 1, illustrating a variation thereof;

[0035]FIG. 4 is a perspective view of a spool gripper according toanother preferred embodiment of the present invention;

[0036]FIG. 5 is an exploded perspective view of a spool handling unitwith the spool gripper; and

[0037]FIG. 6 illustrates the process of handing a spool with the spoolgripper.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0038] Preferred embodiments of this invention will be explained withreference to the accompanying drawings.

[0039]FIG. 1 is a perspective view of a spool gripper according to apreferred embodiment of the present invention, and FIG. 2 is a crosssectional view of the spool gripper taken along the A-A line of FIG. 1.FIG. 5 is an exploded perspective view of a spool handling unit with thespool gripper.

[0040] The spool 10, well known in the art, is wound with a bonding wireW thereon. As shown in the drawings, the spool 10 is formed with acylinder portion (not shown) for winding the bonding wire W thereon, anda pair of small diameter flanges 12 provided at both ends of thecylinder portion. A notch 14 is formed at the one-sided small diameterflange 12 to hold the end portion of the bonding wire W. The end of thebonding wire W passed the notch 14 is fastened to the outer surface ofthe flange 12 by way of a tape 16.

[0041] A spool gripper 20 is coupled to one of the flanges 12 such thatit can be decoupled from the flange 12. The spool gripper 20 is formedfrom a plastic material while bearing a plate ring shape. The spoolgripper 20 has an inner diameter portion 22 bearing a diameter identicalto or lager than the inner diameter portion 18 of the spool 10, acoupling portion 24 coupled to the circumference of the flange 12 whilebearing a diameter larger than the inner diameter portion 22, and anouter diameter portion 26 bearing a diameter lager than the couplingportion 24. With the handling of the spool 10, the worker grips theouter diameter portion 26 of the spool gripper 20.

[0042] At least two coupling protrusions 24′, preferably three couplingprotrusions 24′ are equidistantly formed at the coupling portion 24 tohold the flange 12 while being inwardly protruded in a radial manner.The coupling protrusions 24′ are positioned at the periphery of thecoupling portion 24 while bearing a height corresponding to thethickness of the flange 12.

[0043] A plurality of prominent portions 28′ are formed at the gripper20 to make a space 28 for receiving the end of the conductive wire Wfastened to the outer surface of the spool flange 12 by way of a tape.When the gripper 20 is coupled to the spool flange 12, the end of theconductive wire W is placed within the space 28, and hence, possibledamage thereof can be prevented.

[0044] Meanwhile, the gripper 20 bears cutting planes 28″. When theworker grips the gripper 20, the gripper 20 can be transformed whilecompressing the inner diameter portion 22, due to the presence of thecutting planes 28″.

[0045] Accordingly, with the gripping of the gripper 20, the spool 10can be securely coupled to the gripper 20 without separation.

[0046] A pair of knobs 26′ are formed at the outer diameter portion 26while facing each other. It is preferable that the knobs 26 should bespaced apart from the cutting planes 28″ by the same distance.

[0047] With the knobs 26′, the contamination and damage of theconductive wire can be further effectively prevented.

[0048] When the gripper 20 is coupled to the spool flange 12, thedistance of the bonding wire wound on the spool 10 to the outer diameterportion 26 of the gripper 20 becomes enlarged by a predetermineddimension W1, compared to the small diameter flange 12. Furthermore, thehandling of the spool 10 can be made without directly touching the spool10 due to the knobs 26′. In this way, the contamination and damage ofthe conductive wire W due to the touching of the worker's fingersthereon can be prevented. Furthermore, the coupling state of the gripper20 is not released unless the gripper 20 is intentionally decoupled fromthe flange 12. The insertion of the spool holder 40 is made through theinner diameter portion 22 of the gripper 20 so that the wire bondingoperation can be performed with the coupling of the gripper 20 to theflange 12. Consequently, it is not needed to decouple the gripper 20from the flange 12. In this way, the durability of the gripper 20 isenhanced. Particularly, abrasion of the coupling protrusions 24′ isprohibited as much as possible while securing the reliability of thespool holding.

[0049]FIG. 3 illustrates a variation of the gripper where the couplingprotrusion 24′ is formed at the center of the coupling portion 24. Othercomponents and structures of the gripper are the same as those of thegripper shown in FIGS. 1 and 2.

[0050] The coupling protrusion 24′ should be formed at the same height has the thickness t of the flange 12 to fit the gripper 20 to the flange12. With the placing of the coupling protrusion 24′ at the middle of thecoupling portion 24, the thickness of the outer diameter portion 26 isenlarged by a predetermined degree t2. Accordingly, when the workergrips the gripper 20, the fingers of the worker do not touch theconductive wire W.

[0051]FIG. 4 is a perspective view of a spool gripper 20 a according toanother preferred embodiment of the present invention. The gripper isformed with a metallic material. As the metallic material-based grippercannot be inwardly transformed in a radial manner, it is formed with aplate ring having no cutting plane (as indicated by 28″ in FIG. 1).

[0052] A unit for handling a spool and a method of handling the spoolwill be now explained with reference to FIGS. 5 and 6.

[0053] The spool handling unit with the above-structured gripper 20 hasa spool case 30 for storing and carrying the spool 10.

[0054] The spool case 30 is formed with synthetic resin based on acryl,polyolefin, or styrene. The spool case 30 has a base 32, and a cover 34coupled to the base 32.

[0055] The base 32 is formed with a bottom portion 32 a, a sidewall 32 bprotruded from the bottom portion 32 a, and a protrusion 32 c protrudedfrom the bottom portion 32 a internal to the sidewall 32 b. The innerdiameter portion 18 of the spool 10 is inserted onto the protrusion 32c.

[0056] The cover 34 is fitted to the outer surface of the sidewall 32 bfrom the top of the base 32 to prevent the bonding wire W of the spool10 from being contaminated due to a foreign material such as dust. Thecover 34 has a protrusion 34 b inserted into the inner diameter portion18 of the spool 10 to maintain the central axis of the spool 10 in thehorizontal direction, corresponding to the protrusion 32 c of the base32.

[0057] The protrusion 32 c of the base 32 and the protrusion 34 b of thecover 34 are formed with a circular plane shape such that the diameterthereof is identical to or smaller than the inner diameter of the spool10. The length of the protrusions 32 c and 34 b is established to be 30%of the length of the spool 10.

[0058] The sidewall 34 c bent from the top portion 34 a of the cover 34is formed with a cone shape, which is tapered toward the top portion 34a. A stopper 34 d is formed at the sidewall 34 c of the cover 34 to makethe central axis of the spool 10 be maintained to be in the horizontaldirection.

[0059] The spool case may be differently structured with suitablemodifications.

[0060] With the use of the spool handling unit, the spool 10 wound withthe bonding wire W thereon is fitted to the bottom 32 a of the base 32in an erect posture such that the gripper 20 is positioned at the topside (the cover side). The cover 34 is coupled to the base 32 from thetop side of the base 32 such that the protrusion 34 b of the cover 34 isinserted into the inner diameter portion 18 of the spool 10.

[0061] In this state, the spool case 30 is put on a table (not shown)such that the stopper 34 d is directed toward the bottom.

[0062] As the central axis of the spool 10 is maintained to be in thehorizontal direction, the bonding wire W wound on the spool 10 uniformlydistributes its own weight, its vibration in the movement or handlingthereof and other impacts over its entire length so that the undesirablewinding or releasing of the wire can be effectively prohibited, and therolling of the spool case 30 can be avoided.

[0063] In case the spool 10 is fitted to the spool holder 40 of the wirebonding assembly (not shown), the worker grips the base 32 by one handand, in that state, grips the sidewall of the cover 34 by the otherhand. Thereafter, the cover 34 is lifted upward to thereby decouple thecover 34 from the base 32.

[0064] With the gripping of the knob 26′ of the gripper 20, the spool 10is fitted to the spool holder 40 while being moved in the arrowdirection. At this time, the end portion 42 of the spool holder 40passes the inner diameter portion of the spool 10 and the gripper 20. Inthis way, irrespective of the length of the spool holder 40, thecoupling or decoupling of the spool 10 can be made. Furthermore, in thecase of the spool holder with a holder knob at its end portion 42, thecoupling or decoupling of the spool 10 can be made irrespective of thepresence of the knob 26′ of the gripper 20.

[0065] In this way, the spool 10 is fixedly fitted to the spool holder40 by way of a spool fixation member 44 and/or a holder knob (notshown). In the wire bonding operation, the gripper 20 is constantlyfitted to the flange 12 of the spool 10.

[0066] When the spool 10 is separated from the spool holder 40 toexchange it, the knob 26′ of the gripper 20 fitted to the flange 12 ofthe spool 10 is gripped, and the spool 10 is drawn in the directionopposite to the arrow direction, thereby completing the separation ofthe spool 10.

[0067] As with the conventional spool having a large diameter flange, inthe inventive structure, the distance between the bonding wire wound onthe spool and the outer diameter portion of the gripper becomes enlargedto be greater than that related to the conventional small diameterflange.

[0068] Therefore, the handling of the spool can be made without directlytouching the spool. Furthermore, as a knob is formed at the outerdiameter portion of the gripper, the possible contamination and damageof the conductive wire due to the finger touching can be prevented.

[0069] Furthermore, the coupling state of the gripper to the spool isnot released unless the gripper is intentionally separated from theflange. As the wire bonding operation is made with the gripper beingcoupled to the flange, it is not needed that the gripper should bedecoupled from the flange to make the wire bonding operation.Accordingly, the durability of the gripper and the reliability in thespool holding can be maintained without deterioration while preventingseparation of the spool from the gripper.

[0070] As the gripper involves a space for receiving the end portion ofthe conductive wire, the possible damage to the conductive wire due tothe gripper can be prevented.

[0071] As the conventional spool or spool case is used without anymodification, the production cost can be reduced. The central axis ofthe spool is placed at a horizontal plane in a stable manner.Accordingly, the bonding wire W wound on the spool deals well with itsown load, vibration in its movement and other impacts over its entirelength while effectively preventing the unintended winding or releasingthereof.

[0072] With the inventive gripper, the facility cost is not increasedwhile satisfying the requirements of the package manufacturing company.In case spools are delivered to the package manufacturing company wherethe desired spool has a large diameter flange, the delivery is made withthe gripper being coupled to the flange of the spool. Therefore, anadditional facility for making a large diameter flange is not needed.

[0073] With the inventive spool handling unit, the spool is fitted tothe spool holder using a gripper. Therefore, irrespective of the lengthof the spool holder or the presence of the spool fixation member, thespool handling unit can be used with any type spool holder. As the spoolhandling process is similar to that related to the conventional spool,any confusion is not made to the worker.

[0074] While the present invention has been described in detail withreference to the preferred embodiments, those skilled in the art willappreciate that various modifications and substitutions can be madethereto without departing from the spirit and scope of the presentinvention as set forth in the appended claims.

I claim:
 1. A spool gripper for coupling to flanges provided at bothsides of a spool wound with a semiconductor device bonding wire thereon,the spool gripper comprising: an inner diameter portion configured toreceive a spool holder when the spool is fitted to the spool holder; acoupling portion configured to be couplable to a circumference of theflange and having a diameter larger than the inner diameter portion; andan outer diameter portion with a diameter larger than the couplingportion, the outer diameter portion being grippable for handling thespool.
 2. The spool gripper of claim 1, wherein at least two couplingprotrusions are formed at the coupling portion so as to protrudeinwardly in a radial manner.
 3. The spool gripper of claim 2, whereinthe coupling protrusions are positioned at a periphery of the couplingportion.
 4. The spool gripper of claim 2, wherein the couplingprotrusions are positioned at a center of the coupling portion.
 5. Thespool gripper of claim 2, further comprising a plurality of prominentportions arranged to form a space for receiving an end portion of theconductive wire fitted to the flange.
 6. The spool gripper of claim 1,wherein a pair of knobs are formed at the outer diameter portion so asto face each other.
 7. The spool gripper of claim 1, further comprisinga cutting plane through the inner diameter portion, the coupling portionand the outer diameeter portion so that the gripper is compressable todeform the inner diameter.
 8. The spool gripper of claim 1, furthercomprising a plurality of prominent portions arranged to form a spacefor receiving an end portion of the conductive wire fitted to theflange.
 9. A spool handling unit, comprising: a spool gripper having aninner diameter portion configured to receive a spool holder when thespool is fitted to the spool holder, a coupling portion configured to becouplable to a circumference of the flange and having a diameter largerthan the inner diameter portion, and an outer diameter portion with adiameter larger than the coupling portion, the outer diameter portionbeing grippable for handling the spool; and a spool case for storing thespool, the spool case having a base for mounting the spool, and a covercoupled to the base to prevent foreign materials from being introducedinto the case.
 10. The spool handling unit of claim 9, wherein the basehas a bottom portion, a sidewall protruded from the bottom portion, anda protrusion formed at the bottom portion internal to the sidewall so asto be insertable into an inner diameter portion of the spool, the coverhaving a protrusion insertable into the inner diameter portion of thespool fitted to the base to maintain a central axis of the spool in ahorizontal direction, and a stopper configured so as to hold the centralaxis of the spool in the horizontal direction.
 11. A method of handlinga spool with a spool handling unit having a spool gripper with an innerdiameter portion configured to receive a spool holder when the spool isfitted to the spool holder, a coupling portion configured to becouplable to a circumference of the flange and having a diameter largerthan the inner diameter portion, and an outer diameter portion with adiameter larger than the coupling portion, the outer diameter portionbeing grippable for handling the spool, and a spool case for storing thespool, the spool case having a base for mounting the spool and a covercoupled to the base to prevent foreign materials from being introducedinto the case, wherein the base has a bottom portion, a sidewallprotruded from the bottom portion, and a protrusion formed at the bottomportion internal to the sidewall so as to be insertable into an innerdiameter portion of the spool, the cover having a protrusion insertableinto the inner diameter portion of the spool fitted to the base tomaintain a central axis of the spool in a horizontal direction, and astopper configured so as to hold the central axis of the spool in thehorizontal direction, the method comprising the steps of: coupling thespool gripper to the flange of the spool; mounting the spool to thespool case; storing and carrying the spool so that the central axis ofthe spool is maintained to be in the horizontal direction; gripping thespool gripper coupled to the spool; fitting the spool to the spoolholder; and performing a wiring bonding operation while the gripper iscoupled to the spool.